Stapler



Sept. 27, 1966 o. H. JoHNsoN STAPLER Filed July 22, 1964 INVENTOR.

OSCAR H. JOHNSON FIG.5

United States Patent O 3,275,212 STAPLER Oscar H. Johnson, Holden,Mass., assigner to Parker Mfg.

Company, Worcester, Mass., a corporation of Massachusetts Filed July 22,1964, Ser. No. 384,336 7 Claims. (Cl. 227-132) This invention relates toa stapler and, more particularly, to apparatus arranged to drive wirestaples for fastening and like purposes.

According to `common practice, stapling guns are provided with a,spring-loaded hammer which -drives a wire staple. The hammer isretracted against spring pressure `by a hammer lifter which, at theupper end of the retraction stroke, engages a cam surface which servesto disengage the lifter from the hammer. In previously known Staplers,however, the act of tiring the gun causes the gun to change its positionin the hand of the user in such a way that, by the end of the tiringstroke, the base of the stapling gun is no longer parallel to thesurface into which the staple is to be driven. This results in amalfunctioning of the stapling driving operation and to improperfastening with the staple. Another diiculty experienced with thepreviously-known stapling guns is that the spring pressure at tiring isset in accordance with the Iheaviest staple to be driven. If alight-weight staple is to be used, the driving pressure is,nevertheless, the same amount and requires not only a considerableamount of extra work on the part of the user but, also, in the case oflight staples, results in an improper driving force. When the force istoo heavy, the staple may not be driven properly. Furthermore, thehammer actuating mechanism previously used is quite complicated andexpensive and liable to be easily put out of order. These and otherdifculties experienced with the prior art devices have been obviated ina novel manner by the present invention.

It is, therefore, an outstanding object of the invention to provide astapler in which it is possible to maintain the line of staple iiring ata iixed position during the operation of the gun.

Another object of this invention is the provision of a stapler in whichIthe loperating force for driving the staple may be changed by the user.

A further object ofthe present invention is the provision of a staplerhaving a simple operating mechanism which is inexpensive to manufactureand which is capable of a long life of useful service.

It is another object of the instant invention to provide a stapling gun-in which the geometric relationship between the fixed parts of the gunand the movable operating lever .are such that the gun Ican be kept in aiixed relationship to the surface to be stapled without tiring theoperator.

It is a further object of the invention to provide a stapling gun inwhich the spring pressure for the staple driving operation may bechanged to provide mo-re effective driving and to make the operationless tiresome to the user.

With these and other objects in view, as will be apparent to thoseskilled in the art, the invention resides in the combinaiton of partsset forth in the specification and covered by the claims appendedhereto.

The invention, however, may be best understood by reference to one ofits structural forms as illustrated by the accompanying drawings inwhich:

FIG. 1 is a perspective view of a stapler embodying the principles ofthe present invention,

F-IG. 2 is a vertical sectional view of the stapler,

FIG. 3 is a vertical sectional view of the stapler taken on the lineIII-III of FIG. 2,

"ice

FIG. 4 is `an inclined sectional View of a portion of the inventiontaken on the line IV-IV of FIG. 2,

FIG. 5 shows the same view as FIG. 3 but with the par-ts in a differentrelationship, and

FIG. 6 shows different operating positions of a rnodiiication of theinvention.

Referring yiirst to FIG. 1, which best shows the general features of theinvention, the stapler, indicated generally by the reference numerali10, is shown as having a hollow housing 1=1 from one end of whichextends at a right angle a base 12. At the other end, a grip 13 extendsat a su-bstantal angle to the housing. Between the base and grip extendsan actuating trigger` 14 which, in its position of repose, as shown inFIG. 1, extends parallel to the base 12. When the -trigger Iis at theother end of its stroke, however, it resides generally parallel -to thegrip 13, as shown in dotted lines in FIG. 2.

Extending along lthe base |12 and hingedly attached to its `outer end isa carrier .15 adapted to be loaded with staples; the free end of -thiscarrier is held in place against the base by a latch 116. At the upperpart of the housing -11 is located a slot 17 in which is carried adetent button l18.

Referring now to FIGS. 2 and 3, it can be .seen that a g hammer 19slides vertically within the housing and is pressed to a downwardposition by a coil spring 21. At its other end, the spring pressesupwardly against a cap 22 which consists of a block `of metal slidablein the housing and protruding from the top thereof. Underneath thehammer 19, the base 12 is provided with a block 23 of rubber, and thehammer itself is provided with an operating blade 24 in the usual way.Slidable in the base 12 is a follower 25 which is pressed toward theblade 24 by Ian elongated spring y2'6 contained in the carrier 15.

As is evident in FIG. 2, the grip 13 has the shape of a pistol grip andits general tcentreline extends at an obtuse angle to the general lineof movement of the hammer r19. ln the preferred embodiment, it is madeof a plastic and is configured to t the hand of the user verycomfortably.

The cap 22 is provided with a horizontal bore 27 in which is carried thedetent button 18. As Iis evident in FIGS. 3 `and 5, the cap 22 isvertically slidable between parallel spaced Walls 28 and 29 of thehousing 11. The slot 17 appears in the wall t28, while a similar slot 31is formed in the wall 29. Each of these slots 17 and 31 are similar.keyhole slots having a narrow portion above and a wide circular portionbelow, as is evident in dotted tlines in FIG. 2. The button 18 consistsof a head 32, a shank y33 which exactly tits in the upper narrow partsof the slots 17 `and 311, .a head 34, and a reduced portion 35, whichreduced portion is the same size as the shank 33. The two heads 32 andA34 are also the same diameter and ttit only the enlarged bottom portionof the slots 17 and 31. Extending into the ca-p 22 parallel to the bore27 is a small bore 36 (see FIG. 2) in Vwhich resides a coil spring 37. Ashallow circular recess 38 is provided as a counterbore to the bore 27and is exactly the proper size t-o receive the head 34 in the mannershown in FIG. 3.

A lever 39 is pivotally mounted in the housing 11 on a pivot pin 41. Atits other end adjacent the spring 21 it has pivotally mounted on it alifter 42 which is connected t-o the lever by a pivot pin 43. Thetrigger 14 is pivotally mounted in the housing 11 by means of a pivotpin 44 and at a position spaced from the pivot pin 44 is provided with aroller 4S mounted on an axle 46.

As is evident in FIG. 4, the lever 39 is formed of two side anges 47 and48 joined by a web 49. The flanges 47 and 48 are each provided with anotch 51 (see FIG. 2) directed toward .the lifter 42. Between theflanges 47 and 4S lies a bracket 52 stamped from sheet metal and havinglegs 53 and 54 extending laterally into the notches 51 in 3 the `flanges47 and 4S. The bracket is provided with a finger 55 which is directedtoward the lifter 42 which, in turn, is provided with a lug 56. Betweenthe lug 56 of the lifter `42 and the linger 55 of the bracket 5-2extends a coil spring 57. Also of interest is the fact that a thumbguard 58 is provided in connection with the trigger 14 to prevent .theuser from getting his hand caught in the internal workings of the gun.`Also, the latch 16 is pivoted on ay pivot pin 59 and is maintained inlocking position by a wire spring 61.

Referring to FIIG. 6, which shows a modification of the spring-pressurechanging apparatus, it can be seen that a detent button 62 consists oftwo separated portions 63y and 64 pressed apart by a coil spring 65. Thetwo portions are slidably carried in a bore 66 in the cap 67. As before,the housing is provided with two spaced parallel walls 68 and 69 havingkeyhole sl-ots 71 and 72, respectively. The portion 63' is provided witha reduced end which ts in the narrow upper portion of the slot 71 and alarger portion which tits in the large part of the slot 71, thislast-named portion being not quite as large as the main body of theportion 66 of the detent button which rides in the bore 66. The portion64 is similarly arranged in connection with its slot 72.

The operati-on of the invention will now be readily understood in viewof the above description. With the carrier 1-5 held in place against thebase 12 by the latch 16, the user grasps the grip 13 in the heel of hishand and wraps his ngers around the trigger 14. His forefinger would bepressed forwardly against the guard S8. The trigger 14 is then drawnslowly toward the grip 13. The trigger rotates about its pivot pin 44carrying the roller 45 up against the web 49 of the lever 39. Thiseventually causes the lever to rotate counterclockwise (as viewed inFIG. 2) about the pivot pin 41 and lifts the other end of the leverupwardly. The lever, therefore, operates through the pivot pin 43 tocarry the lifter 4-2 upwardly. The lifter engages a suitably shapedrecess in the hammer 19` and, therefore, carries the hammer upwardlyagainst the pressure of the coil spring 21. Eventually, the upper end ofthe lifter 42 engages a cam surface in the usual way, as shown in dottedlines in FIG. 2. This cam causes the upper end of the lever to be movedto the left, thus causing the lower end t-o be moved to the right and toleave the recess in the hammer 19. The hammer thus released travelsdownwardly striking against the rubber block 23. In the meanwhile,however, during the upward travel of the hammer 19, the follower 2S,under the action of the spring 26, pushes the staples against the insidesurface of the housing 11, so that one staple occupies the positionoriginally occupied by the blade 24. When the hammer moves downwardly,the blade, therefore, strikes the staple and drives it into the work.

Depending on the size of the staples and the type of work t-o be done,it is desirous that the position of the upper end of the spring 21 bechanged so that the spring pressure at the start of the downward strokeof the hammer is exactly the right am-ount. -If a light stroke isdesired, the cap 22 should be adjusted in the housing so that it extendsupwardly o-f the housing. When a higher spring pressure is desired, thecap should be in a lower position. This lower position is shown in FIGS.1 and 2 of the drawings; the position of the button detent 18 would bethe one shown in FIG. of the drawings. In that position, the head 32resides in the lower enlarged part of the slot l17, while the head 34resides in the enlarged lower part of the slot 31. The cap 22 is in itslower position. The spring 36 operates on the inner surface of the head34 and maintains the entire detent button 18 in its lefthand position sothat it cannot move upwardly, even though the spring 21 presses againstthe bottom of the cap 22. In this condition, the spring 21 is under itsgreatest compression at the top of the stroke (just before t-he lifter42 is removed from the hammer) and the greatest force results when thehammer strikes the staple.

l It also requires the greatest amount of work on the part of the userof the gun, and this position should not be used unless this extra forceis necessary properly to drive the staple.

If it is desired to provide a smaller spring force, the operatingmechanism is set in the condition shown in FlIG. 3. To accomplish this(the apparatus being in the condition shown in FIG. 5), the user pressesagainst the reduced portion 35 of the detent button, so that it movesinto the recess 38 in the cap 22, despite the pressure of the spring 36.Then, it is possible to move the shank 33 and the reduced po-rtion 35 upinto the upper narrow portion of the slots 17 and 31. The cap 22 is thenin its high position and the spring pressure would be less at the timeof the release of the hammer 19. In order to return the apparatus to thecondition shown in FIG. 5, where a high force is obtained from thespring, it is only necessary to hold the housing 11 in one hand andpress downwardly on the cap 22. When the detent button 18 reaches thebott-om of the slots 17 and 31, the spring 36 will press it to the rightand the heads 32 and 34 will move into the enlarged lower portions ofthe slots and lock them in place.

When a gun constructed in accordance with the present invention isoperated, it can be seen that the operator keeps the heel of his handagainst the upper part of the grip 13, so that the entire fixed portionsof the gun, Le., the grip 13, the housing 11, and the base 12, remainfixed relative to the rest of his arm and body. It is possible,therefore, to keep the gun pointed in an exact accurate direction byusing this method. The lingers serve to operate the trigger 14, but thisdoes not change the position of the gun as was true of previously-knowndevices of this kind. It should be observed that the spring 57 whichoperates between the lifter 42 and the lever 39 maintains them at thegreatest obtuse angle possible unless the trigger 14 dictates otherwise.Thus, the trigger in its normal position will be pressed downwardly intoa position generally parallel to the base 12. The roller 45 in operatingon the lever 39 simply rolls along the bottom of the web 49' whichproduces a very smooth action and a large mechanical advantage.

The operation of the detents in FIG. 6 are such that inward pressure onthe portions 63 and 64 will permit them to be moved upwardly into thenarrow portions of the slots 71 and 72, so that the cap 67 can occupy ahighpower position. When it is desired to move to a lowpower positionand move the cap 67 downwardly, it is only necessary to press the cap 67downwardly so that the two portions 63 and 64 of the detent button 62move outwardly and the next or enlarged portion of the parts move intothe enlarged lower portion of the slots 71 and 72 and are locked in thatposition.

It can be seen, then, that by the operation of the present invention, itis possible to change the spring pressure at the moment of hammerrelease to either of two desired positions, i.e., a lightor aheavy-power position. The change from one to the other is easilyaccomplished by relatively simple mechanism. It is possible to drivestaples not only in a comfortable position of the hand and arm but alsowithout rotating the entire gun during the stapling operation because ofthe need to press a trigger with the heel of the hand, as in thepreviously-known practice. Furthermore, the operating mechanism is notonly smoothly operating but, because of this smoothness, is capable of along life of useful service. There are no intense force factors involvedthat tend to break and wear the mechanism.

It is obvious that minor changes may be made in the form andconstruction of the invention without departing from the material spiritthereof. It is not, however, desired to confine the invention to theexact form herein shown and described, but it is desired to include allsuch as properly come within the scope claimed.

The invention having been thus described, what is claimed as new anddesired to secure by Letters Patent is:

1. A stapler, comprising (a) an elongated base adapted to carry a supplyof staples and to feed them toward one end,

(b) an elongated housing extending at a right angle to the said base andhaving a hammer movable longitudinally of the housing toward the saidone end to drive a staple,

(c) an elongated cantilevered grip extending at a sub stantial angle tothe housing at the end opposite the end which is associated with thebase,

(d) a trigger for actuating the hammer hingedly fastened to the saidhousing between and extending in the same general direction as the baseand the grip,

(e) a spring in the housing pressing with one end against the saidhammer,

() a cap mounted in the housing and engaging the other end of thespring,

(g) means connecting the housing and the cap to lock the cap in one of aplurality of accurately-spaced positions relative to the housing for theselection of spring pressure and hammer force,

(h) a lever mounted in the housing for pivotal movement about one end,

(i) a lifter pivotally mounted on the other end of the lever and havinga hook at one end for engagement with the hammer, and

(j) a roller mounted on the actuating trigger and engaging the leverbetween the ends.

2. A stapler, comprising (a) a base adapted to carry a supply of staplesand to feed them to a driving position,

(b) a housing connected to the base and having a hammer movable towardthe said driving position on the base to drive a staple,

(c) a spring in the housing biasing the hammer toward the said drivingposition,

(d) an actuating handle hingedly mounted on the housing,

(e) a lever consisting of two spaced, parallel anges joined by a webmounted in the housing for pivotal movement about one end,

(f) a lifter pivotally mounted on the other end of the lever and havinga hook at one end for engagement with the hammer,

(g) a roller mounted on the actuating handle and engaging the leverbetween the ends, and

(h) a spring extending between the lever and the lifter and acting alonga line substantially spaced from the axis of pivotal connection betweenthe lever and the lifter, the spring embracing at one end a pegextending from the lifter and at the other end embracing a nger on abracket associated with the lever, each flange of the lever beingprovided with a notch directed toward the lifter, the bracket lyingbetween the anges and having laterally extending legs which lie in thesaid notches. 3. A stapler, comprising (a) a base adapted to carry asupply of staples and to feed them to a driving position, (b) a housingconnected to the base and having a hammer movable toward the saiddriving position on the l base to drive a staple,

(c) a spring in the housing pressing with one end against the saidhammer (d) a cap mounted in the housing and engaging the other end ofthe spring, the cap being slidably mounted between opposite parallelwalls of the housing, two identical apertures being formed in the saidparallel walls, and

(e) means connecting the housing and the cap to lock the cap in one of aplurality of accurately-spaced positions relative to the housing for theselection of spring pressure and hammer force, the means cornprising abutton detent mounted in the cap for engagement with the apertures.

4. A stapler as recited in claim 3, wherein the apertures arekeyhole-shaped and have a narrow portion and a large portion and whereinthe button detent has a large portion fitting closely within the largeportion of the aperture and a narrow portion fitting closely within thenarrow portion of the aperture.

5. A stapler as recited in claim 3, wherein the detent consists of twocylindrical elements arranged end-to-end in a bore extending through thecap between the two apertures and wherein a spring lies between the twoelements to bias them outwardly into the apertures.

6. A stapler as recited in claim 4, wherein the detent has two spacedheads adapted to t in the large portions of the slots and Shanks adaptedto fit in the narrow portions of the slots and wherein a spring biasesthe detent toward a position in which the heads reside in the said largeportions.

7. A stapler as recited in claim 6, wherein a counterbore is provided inthe cap coaxial of the said bore to receive one lof the heads of thedetent on occasion and wherein `a small bore extends into the capparallel to the bore and opens in the said counterbore to receive thelast-named spring.

References Cited by the Examiner UNITED STATES PATENTS 1,919,373 7/1933Krantz 227-132 2,361,483 10/1944 Lang 227-132 2,492,509 12/ 1949Vandervieren 227-132 3,149,339 9/1964 Johnson 227-132 GRANVILLE Y.CUSTER, JR., Primary Examiner.

1. A STAPLER, COMPRISING (A) AN ELONGATED BASE ADAPTED TO CARRY A SUPPLYOF STAPLES AND TO FEED THEM TOWARD ONE END, (B) AN ELONGATED HOUSINGEXTENDING AT A RIGHT ANGLE TO THE SAID BASE AND HAVING A HAMMER MOVABLELONGITUDINALLY OF THE HOUSING TOWARD THE SAID ONE END TO DRIVE A STAPLE,(C) AN ELONGATED CANTILEVERED GRIP EXTENDING AT A SUBSTANTIAL ANGLE TOTHE HOUSING AT THE END OPPOSITE THE END WHICH IS ASSOCIATED WITH THEBASE, (D) A TRIGGER FOR ACTUATING THE HAMMER HINGEDLY FASTENED TO THESAID HOUSING BETWEEN AND EXTENDING IN THE SAME GENERAL DIRECTION AS THEBASE AND THE GRIP, (E) A SPRING IN THE HOUSING PRESSING WITH ONE ENDAGAINST THE SAID HAMMER, (F) A CAP MOUNTED IN THE HOUSING AND ENGAGINGTHE OTHER END OF THE SPRING, (G) MEANS CONNECTING THE HOUSING AND THECAP TO LOCK THE CAP IN ONE OF A PLURALITY OF ACCURATELY-SPACED POSITIONSRELATIVE TO THE HOUSING FOR THE SELECTION OF SPRING PRESSURE AND HAMMERFORCE, (H) A LEVER MOUNTED IN THE HOUSING FOR PIVOTAL MOVEMENT ABOUT ONEEND, (J) A LIFTER PIVOTALLY MOUNTED ON THE OTHER END OF THE LEVER ANDHAVING A HOOK AT ONE END FOR ENGAGEMENT WITH THE HAMMER, AND (J) AROLLER MOUNTED ON THE ACTUATING TRIGGER AND ENGAGING THE LEVER BETWEENTHE ENDS.